1. Field of the Invention
This invention relates to a braking system, and more particularly to a steering brake system for use in track-type vehicles.
2. Description of the Prior Art
In a track-type vehicle having a steering clutch system, a steering brake system such that it is operated by means of an operating member, such as, for example, a brake pedal, by which the steering clutch is also operated in a predetermined time lag has been heretofore well known. The steering brake system of this type is properly used for applying to the vehicle a normal brake and an emergency one by the action of a variable pressure reducing valve operated by the depression of the brake pedal so as to increase the safety of the vehicle. The proper use of the steering brake system is dependent upon a degree of the depression of the brake pedal. In such steering brake system, the emergency brake is performed by urging an emergency brake piston slidably inserted within a brake cylinder to its braking position by the action of a spring provided within the brake cylinder. In order to release the emergency brake in the above-mentioned conventional system, it is therefore essential to apply a hydraulic pressure to a pressure receiving chamber defined by and between the brake cylinder and the emergency brake piston to move the piston in its nonbraking position against the action of the spring. For this reason, the foregoing prior art steering brake system is disadvantageous in that, if the engine of the vehicle is stopped or is in a low idling under such a condition that the emergency brake is applied thereon, the emergency brake cannot be released, accordingly it is difficult to move the vehicle.